Table 1. Outcome measures collected at baseline and follow-up.

Measure:	Baseline:	Six-Month Follow-up:	12-Month Follow-up:	18-Month Follow-up:	24-Month Follow-up:
UPDRS (Parts I-IV) (ON^†)	38	32	27	22	20
UPDRS-III (ON)	13	14	8	6	9
UPDRS-III lateralized²⁷ scores (ON) (R/L)	6 / 4	3 / 7	2 / 5	2 / 4	3 / 6
UPDRS-III (OFF^‡)	20	23	19	25	24
UPDRS-III lateralized²⁷ scores (OFF) (R/L)	9 / 6	10 / 7	8 / 8	10 / 11	12 / 8
% time ON with dyskinesias	0	0	0	0	0
Anti-PD medications (levodopa equivalents)^28,29	225	133	133	436	361
IPG amplitude setting^§ (R/L)	N/A	1.5 / 1.5	1.8 / 1.8	1.8 / 1.8	1.8 / 1.8
PDQ-39	8.91		UTD^*		2.34

^†

ON refers to ON stimulation/ON medication (collected on day 1 of inpatient evaluation)

^‡

OFF refers to OFF stimulation/OFF medication (collected on day 8 of inpatient evaluation, after 7-day washout period)

^§

§All other stimulation parameters remained constant throughout the two-year follow-up period: monopolar configuration with the case set to positive and the active contact set to negative (Left: contact 2; Right: contact 1) at a pulse width of 60 μs and frequency of 130 Hz.

Unable to do: one question was left unanswered by the subject. The scoring instructions for the PDQ-39 instrument state that if one item is left unanswered, the overall index cannot be calculated.